Vibration technique for fatigue testing of a sandwich composite

Fatigue lifetime prediction under conventional three-point-bending is generally limited by extensive testing periods. The development of a vibration technique with increased cyclic performance may yield a time and cost effective alternative. A geometric shape optimization procedure using finite element analysis is developed. The methodology produces the specific three-point-bending pattern in a given region while the specimen's vibration occurs at the first resonance mode. The technique is applied to a sandwich composite and compared to three-point-bending results. Lifetime predictions fall within the ninety percent confidence levels of the composite's three-point-bending tests.